— Edward de BonoContext: The rejection process is incorporated in the concept of the negative. The negative is a judgement device. It is the means whereby one rejects certain arrangements of information. The negative is used to carry out judgement and to indicate rejection. The concept of the negative is crystallized into a definite language tool. This language tool consists of the words no and not. Once one learns the function and use of these words one has learned how to use logical thinking. The whole concept of logical thinking is concentrated in the use of this language tool. Logic could be said to be the management of NO.
p. 159.

— Edward de BonoContext: What happened was, 2,400 years ago, the Greek Gang of Three, by whom I mean Aristotle, Plato and Socrates, started to think based on analysis, judgment and knowledge. At the same time, church people, who ran the schools and universities, wanted logic to prove the heretics wrong. As a result, design and perceptual thinking was never developed. People assumed philosophers were doing it and so they blocked anyone else from doing it. But philosophers were not. Philosophers may look out at the world from a stained-glass window, but after a while they stop looking at the world and start looking at the stained glass.

— Edward de BonoContext: There isn't just one point; it takes time to learn. You don't have to be intelligent, but I think you have to be open to possibilities and willing to explore. The only stupid people are those who are arrogant and closed off.

— Edward de BonoContext: Lateral thinking... is the process of using information to bring about creativity and insight restructuring. Lateral thinking can be learned, practised and used. It is possible to acquire skill in it just as it is possible to acquire skill in mathematics.
p. 5; Preface.

— Edward de BonoContext: Design is really a special case of problem solving. One wants to bring about a desired state of affairs. Occasionally one wants to remedy some fault but more usually one wants to bring about something new. For that reason design is more open ended than problem solving. It requires more creativity. It is not so much a matter of linking up a clearly defined objective with a clearly defined starting position (as in problem solving) but more a matter of starting out from a general position in the direction of a general objective
p. 198; Cited in: Eddie Norman, Urry (1995) Advanced design and technology. p. 65-66.

— Edward de BonoContext: With vertical thinking one may look for different approaches until one finds a promising one. With lateral thinking one goes on generating as many approaches as one can even after one has found a promising one. With vertical thinking one is trying to select the best approach but with lateral thinking one is generating different approaches for the sake of generating them.
p. 29.

— Edward de BonoContext: Vertical thinking is selection by exclusion. One works within a frame of reference and throws out what is not relevant. With lateral thinking one realizes that a pattern cannot be restructured from within itself but only as the result of some outside influence. So one welcomes outside influences for their provocative action. The more irrelevant such influences are the more chance there is of altering the established pattern. To look only for things that are relevant means perpetuating the current pattern.
p. 32 as cited in: ACEEE (1994) 1994 ACEEE Summer Study on Energy Efficiency in Buildings. p. 165.

— Edward de BonoContext: What happened was, 2,400 years ago, the Greek Gang of Three, by whom I mean Aristotle, Plato and Socrates, started to think based on analysis, judgment and knowledge. At the same time, church people, who ran the schools and universities, wanted logic to prove the heretics wrong. As a result, design and perceptual thinking was never developed. People assumed philosophers were doing it and so they blocked anyone else from doing it. But philosophers were not. Philosophers may look out at the world from a stained-glass window, but after a while they stop looking at the world and start looking at the stained glass.

— Edward de BonoContext: Creative thinking — in terms of idea creativity — is not a mystical talent. It is a skill that can be practised and nurtured. You can never tell how a policy has been reached just by looking at the end result. Some people who have achieved a huge amount do not come across as impressive when you speak to them.